The term “proprioceptive neuromuscular facilitation” (“PNF”) refers to stretching techniques used in a clinical environment to enhance a patient's both active and passive ranges of motion. Generally, an active PNF stretch involves a shortening contraction of the opposing muscle to place the target muscle on stretch, followed by an isometric contraction of the target muscle.
In the past, PNF treatment involved a therapist using his or her hands to stretch the muscle group of a joint to the end of its current range of motion. Then the patient contracts the muscle group isometrically in the stretched position against resistance from the therapist's hands for a brief period of time. The muscle group is then allowed to relax briefly before being stretched again by the therapist to an increased range of motion when the muscles are again contracted isometrically in the stretched position against resistance by the therapist. This routine is continued until no further range of motion is achieved or the patient becomes fatigued.
In the case of PNF neck therapy, the patient lies on a table with the head extending beyond one end of the table, while the therapist holds the sides of the head and moves the head to a desired position to stretch the target muscle group. Progress is determined by the improved angle of motion of the neck from its normal position. The angle is either estimated or measured using a protractor. Because both hands of the therapist are required during the stretch and hold, a protractor is difficult to use, resulting in inaccurate measurement. The therapist may have a difficult time holding the head in a fixed position against the force applied by the patient's head. Also, the force needed to hold the patient's head is fatiguing for the therapist.